Field
The described technology generally relates to a rotary piston machine and especially a rotary engine.
Description of the Related Technology
Rotary piston machines of this type typically feature a housing, a piston chamber that is defined in the housing by a first sidewall, a second sidewall and a peripheral wall interconnecting these sidewalls and a rotary piston that is rotatably arranged in the piston chamber and has a first face and a second face. In this case, the first face of the rotary piston faces an interior of the first sidewall of the piston chamber and the second face of the rotary piston faces an interior of the second sidewall of the piston chamber. At least two or, in the case of a triangular rotary piston, three working zones are furthermore formed between a peripheral surface of the rotary piston and a peripheral wall of the piston chamber.
In order to prevent so-called blow-by gases from escaping from the working zones into intermediate spaces between the faces of the rotary piston and the sidewalls of the piston chamber during the operation of the rotary piston machine, first lateral seals are provided on the two faces of the rotary piston in order to seal these intermediate spaces relative to the working zones. In order to improve the sealing effect, DE 195 27 396 C2 proposes to elastically pretension the lateral seals, as well as to equip said lateral seals with additional ring seals in the radial direction.
In addition to the aforementioned first lateral seals for sealing the intermediate spaces relative to the working zones, second lateral seals (usually referred to as oil seals) are usually also provided, wherein these second lateral seals are radially positioned within the first lateral seals and serve for sealing the intermediate spaces between the faces of the rotary piston and the sidewalls of the piston chamber relative to the central bore in the rotary piston. Two respective oil seals that are radially spaced apart from one another are frequently provided in order to improve the sealing effect.
Despite the first and second lateral seals provided on the faces of the rotary piston, it cannot always be prevented that blow-by gases escape from the working zones of the piston chamber into the intermediate spaces between the faces of the rotary piston and the sidewalls of the piston chamber.
U.S. Pat. No. 3,849,038 A describes a configuration of a rotary piston machine, in which the intake opening is arranged and shaped in the sidewall of the piston chamber in such a way that a section situated between two radially spaced-apart oil seals, in which blow-by gases can accumulate, passes over this intake opening during the rotation of the rotary piston and the blow-by gases can be discharged from the intermediate space through this intake opening of the piston chamber and returned to the working zones.
According to U.S. Pat. No. 4,080,118 A, recesses are respectively provided in the faces of the rotary piston radially between the first lateral seals and the second lateral seals, wherein the blow-by gases that escape from the working zones through the first lateral seals can accumulate in said recesses. In this embodiment, the blow-by gases are also discharged through the intake opening in the sidewall(s) of the piston chamber while the rotating rotary piston passes over this intake opening.
JP 03-037301 A discloses a rotary piston machine, in which recesses are respectively provided in the faces of the rotary piston radially between the first lateral seals and the second lateral seals thereof and the blow-by gases from the working zones can accumulate in said recesses. The rotary piston is furthermore realized with an axial through-bore that interconnects the recesses in the two faces of the rotary piston. This through-bore makes it possible to realize a pressure reduction of the blow-by gases, as well as a pressure compensation between the blow-by gases to both faces of the rotary piston.
In the rotary piston machine according to WO 2009/101385 A1, the blow-by gases escaping from the working zones through the lateral seals of the rotary piston are utilized for regulating the pressure of a cooling gas flowing through the rotary piston.